Underwater Robot Tracks Elusive Jellyfish

Robison, a deep-sea ecologist at the Monterey Bay Aquarium Research Institute in Moss Landing, Calif., used to work with what he calls "respectable animals"those large enough for research vessels' nets to catch.

"The nets would haul up fish and squid, which were all covered in a clear goo that we'd scrape off the top and throw over the side," Robison says.

Studying that transparent, amorphous "goo"a puree of jellyfish and other gelatinous sea dwellersprovides clues to the nature of the undersea food chain. And the ubiquity of these creatures throughout the world's oceans makes them a silent sentinel of environmental change.

For example, some researchers believe that higher water temperatures from global warming may have boosted the number of comb jellies in Rhode Island's Narragansett Bay, says Larry Madin, a marine biologist at the Woods Hole Oceanographic Institution in Massachusetts.

And a tenfold increase in jellyfish numbers in the Bering Sea, also perhaps climate-related, has led observers to dub one area of the Alaskan peninsula the "Slime Bank."

"I was amazed by how many jellies there are," Robison says. "Just using nets, we've missed about one third of the animals in the oceans."

Chasing Jellies

Robison and his collaborator Jason Rife, a doctoral candidate in a robotics laboratory at Stanford University in California, are venturing out on the high seas with a camera-equipped underwater robot that tracks jelly-like creatures in their own domain.

Rife designed the software and the camera system for the remotely operated vehicle, or ROV, dubbed the Ventana. A cable tethers the ROV to the research ship.

On board the ship, about seven miles off Monterey Bay, one of the researchers in a control booth directs Ventana's movements between 900 and 3,000 feet below the surface until the camera finds a jelly of interest.